Molecular aspects of the receptor activation by imidazolines: an overview.

Based on the pharmacological activity of chiral imidazolines the steric requirements for the activation of the alpha-adrenoceptor are provided. Importantly, the sequence of interaction of the critical groups of the asymmetric carbon of imidazolines and catecholamines with the alpha-adrenoceptor is postulated. Thus, initial determinants of molecular efficacy are hypothesized. The effect of aromatic fluoro-substitution and introduction of a double bond in the imidazoline moiety on the pharmacologic activity is discussed. The unique mechanism of non-adrenergic vascular activity of isothiocyanato-tolazoline is presented.